1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for scheduling in a wireless communication system.
2. Related Art
Long term evolution (LTE) based on 3rd generation partnership project (3GPP) technical specification (TS) release 8 is a promising next-generation mobile communication standard.
As disclosed in 3GPP TS 36.211 V8.7.0 (2009-05) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)”, a physical channel of the LTE can be classified into a downlink channel, i.e., a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH), and an uplink channel, i.e., a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH).
The PUCCH is an uplink control channel used for transmission of an uplink control signal such as a hybrid automatic repeat request (HARQ) positive-acknowledgement (ACK)/negative-acknowledgement (NACK) signal, a channel quality indicator (CQI), and a scheduling request (SR).
Meanwhile, a mobile communication system includes a time division duplex (TDD) system and a frequency division duplex (FDD) system.
In the TDD system, a downlink and an uplink use the same frequency. In the FDD system, a downlink and an uplink use different frequencies. As such, the TDD system and the FDD system use different radio resources, and thus may have different frame structures.
For example, in the FDD system, a downlink subframe and an uplink subframe exist for all time durations in a frame. On the other hand, in the TDD system, a downlink subframe and an uplink subframe may exist in different numbers in a frame.
Conventionally, in the TDD system, an uplink subframe, a downlink subframe, and a special subframe are configured for each subframe in a frame by using a higher layer signal. However, this method has a problem in that it is difficult to allocate resources efficiently when downlink and uplink traffic amounts change dynamically.